> ## Documentation Index
> Fetch the complete documentation index at: https://www.meilisearch.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Bind search analytics events to a user

> This guide shows you how to manually differentiate users across search analytics using the X-MS-USER-ID HTTP header.

## Assign user IDs to search requests

You can assign user IDs to search requests by including an `X-MS-USER-ID` header with your query:

<CodeGroup>
  ```bash cURL theme={null}
  curl \
    -X POST 'MEILISEARCH_URL/indexes/INDEX_NAME/search' \
    -H 'Content-Type: application/json' \
    -H 'Authorization: Bearer DEFAULT_SEARCH_API_KEY' \
    -H 'X-MS-USER-ID: MEILISEARCH_USER_ID' \
    --data-binary '{}'
  ```
</CodeGroup>

Replace `SEARCH_USER_ID` with any value that uniquely identifies that user. This may be an authenticated user's ID when running searches from your own back end, or a hash of the user's IP address.

<Note>
  Assigning user IDs to search requests is optional. If a search request does not include a user ID, Meilisearch automatically generates an anonymous identifier based on the user's browser information. This allows basic tracking across requests while preserving user anonymity.

  However, providing your own user IDs is recommended for more accurate analytics. Auto-generated identifiers may not reliably track the same user across different sessions or devices, which can inflate your total user count and reduce the accuracy of per-user metrics.
</Note>

## Assign user IDs to analytics events

You can assign a user ID to analytics `/events` in two ways: HTTP headers or including it in the event payload. When possible, prefer including the `userId` field directly in the event payload. `X-MS-USER-ID` and other `X-` prefixed headers may be stripped by certain proxies, CDNs, or load balancers.

If using HTTP headers, include an `X-MS-USER-ID` header with your query:

<CodeGroup>
  ```bash cURL theme={null}
  curl \
    -X POST 'https://PROJECT_URL/events' \
    -H 'Content-Type: application/json' \
    -H 'Authorization: Bearer DEFAULT_SEARCH_API_KEY' \
    -H 'X-MS-USER-ID: SEARCH_USER_ID' \
    --data-binary '{
      "eventType": "click",
      "eventName": "Search Result Clicked",
      "indexUid": "products",
      "objectId": "0",
      "position": 0
    }'
  ```
</CodeGroup>

If you prefer to include the user ID in your event payload, include a `userId` field with your request:

<CodeGroup>
  ```bash theme={null}
  curl \
    -X POST 'MEILISEARCH_URL/events' \
    -H 'Content-Type: application/json' \
    -H 'Authorization: Bearer MEILISEARCH_KEY' \
    --data-binary '{
      "eventType": "click",
      "eventName": "Search Result Clicked",
      "indexUid": "products",
      "objectId": "0",
      "position": 0,
      "userId": "SEARCH_USER_ID"
    }'
  ```
</CodeGroup>

<Warning>
  It is mandatory to specify a user ID when sending analytics events.
</Warning>

## Conclusion

In this guide you have seen how to bind analytics events to specific users by specifying an HTTP header for the search request, and either an HTTP header or a `userId` field for the analytics event.